The present invention relates to a method for chamfering the cam plate of a swash plate compressor.
There has been widely used a swash plate compressor, which as shown in FIG. 1, comprises a cylinder block 1 provided with cylinder bores 2, pistons 3 inserted into the cylinder bores 2 to be slidable, a driving shaft 4, a cam plate 5 slantedly fixed to the driving shaft 4 and shoes, 6 inserted between the cam plate 5 and the pistons 3. The cam plate 5 of the swash plate compressor is ellipsoidal. The circumferential surface 5a of the cam plate 5 forms a cylindrical surface extending coaxially with the driving shaft 4 to avoid interference with the pistons 3.
As seen from FIG. 1, the circumferential surface 5a is present between an acute-angled edge 5axe2x80x2 and an obtuse-angled edge 5axe2x80x3. The acute-angled edge 5axe2x80x2 is closer to the pistons 3 than the obtuse-angled edge 5axe2x80x3 and liable to interfere with the pistons 3. Therefore, the acute-angled edge 5axe2x80x2 must be chamfered.
As shown in FIG. 2, the operation of chamfering the acute-angled edge 5axe2x80x2 has been carried out by a method comprising the steps of rotating the cam plate 5 around a central axis X extending coaxially with the driving shaft 4, abutting the blade 7a of a cutting tool 7 against the acute-angled edge 5axe2x80x2 of the circumferential surface 5a, and reciprocating the cutting tool 7 parallel to the central axis X synchronously with the reciprocal movement of the circumferential surface 5a parallel to the central axis X. As seen from FIG. 2, the blade 7a of the cutting tool 7 must be inclined relative to the central axis X in order to chamfer the acute-angled edge 5axe2x80x2 of the circumferential surface 5a rotating around the central axis X with the cam plate 5 to form a cylindrical surface extending coaxially with the central axis X. The cutting tool 7 with its blade 7a inclined relative to the central axis X must be reciprocated synchronously with the reciprocal movement of the circumferential surface 5a in order to chamfer the acute-angled edge 5axe2x80x2. Therefore, the conventional method for chamfering the cam plate of the swash plate compressor requires a special apparatus for reciprocating the cutting tool synchronously with the reciprocal movement of the circumferential surface of the cam plate.
As seen from FIG. 2, an acute-angled edge 5axe2x80x2 is present at each side of the cam plate 5. In the conventional method for chamfering, the chamfering of one of the acute-angled edges 5axe2x80x2 of the circumferential surface 5a causes the chamfering of the obtuse-angled edge 5axe2x80x3 connecting with the chamfered acute-angled edge 5axe2x80x2 and not the chamfering of the other of the acute-angled edges 5axe2x80x2. Therefore, the cutting tool 7 must be abutted against the acute-angled edge 5axe2x80x2 at each side of of the central axis X and from opposite directions in order to chamfer the acute-angled edges 5axe2x80x2 substantially over the whole length thereof. Thus, the conventional method for chamfering requires two chamfering operations.
An object of the present invention is to provide a method for chamfering the cam plate of a swash plate compressor, wherein a special apparatus for reciprocating the cutting tool synchronously with the reciprocal movement of the circumferential surface of the cam plate is not required and a single chamfering operation can chamfer the acute-angled edges of the circumferential surface over substantially the whole length thereof.
In accordance with the present invention, there is provided a method for chamfering the cam plate of a swash plate compressor comprising a cylinder block provided with cylinder bores, pistons inserted into the cylinder bores to be slidable, a driving shaft, a cam plate slantedly fixed to the driving shaft and shoes inserted between the cam plate and pistons, wherein the circumferential surface of the cam plate forms a cylindrical surface extending coaxially with the driving shaft, comprising the steps of rotating the cam plate around an axis inclined relative to the driving shaft, disposing the blade of a cutting tool to extend parallel to the axis, and abutting the blade of the cutting tool against the edges of the circumferential surface of the cam plate.
In the chamfering method in accordance with the present invention, the cam plate rotates around an axis inclined relative to the driving shaft to incline the circumferential surface of the cam plate forming a cylindrical surface extending coaxially with the driving shaft relative to the axis. Therefore, the edges of the circumferential surface can be chamfered by the steps of disposing the blade of the cutting tool to extend parallel to the axis and abutting the blade against the edges of the circumferential surface. The blade of the cutting tool extends parallel to the axis. Therefore, on the sole condition that the blade of the cutting tool is sufficiently long, the blade of the cutting tool can be kept abutting against the edges of the reciprocating circumferential surface of the cam plate to chamfer the edges even if the cutting tool is fixed in the direction of the reciprocal movement of the circumferential surface of the cam plate. Therefore, the chamfering method in accordance with the present invention does not require a special apparatus for reciprocating~the cutting tool synchronously with the reciprocal movement of the circumferential surface of the cam plate.
In the present chamfering method, a single chamfering operation can chamfer the acute-angled edges of the circumferential surface of the cam plate substantially over their whole length because the blade of the cutting tool can always oppose the acute-angled edges of the circumferential surface of the cam plate.